I have 64bit CPU but I can't boot/install 64bit guests?

You might see variants of this error: "Host CPU is incompatible with the virtual machine's requirements at CPUID level 0x80000000001 register 'edx'."

64bit guest OSes require additional support from the hardware when executed in the virtual environment. On Intel, this is called Intel VT. On AMD it is AMD-V.

Both Intel VT and AMD-V are hardware based virtualization extensions in the CPU and chipset hardware of the host. Most modern systems should support them, however systems from 2005 or before may or may not have support present. Virtualization features are usually enabled in the BIOS of the hardware, and can be disabled per-VM basis in some virtualization products.

VMware has made a tool available for checking VT status, downloadable at http://ftpsite.vmware.com/download/vt.iso.

Here's the fix:

I figured out the solution through trial and error. You have to go to the CPUID mask for the VM Advanced Options and change the 0×800000001 register edx to

–1- —- —- —- —- —- —- —-

By default it’s set to:

—- —- —1 —- —- —- —- —-

The dashes are 0 bits.

Once you make this change, you should be able to start up the x64 VM without a problem. It’s stupid that this needs to be done, but until VMWare figures out a way to correct this, I guess this tweak will have to do.